1. Field of the Invention
The present invention relates to an apparatus for connecting an optical universal serial bus (USB) (or an optical serial bus; OSB) device and an electrical USB device, and a structure of the apparatus. More particularly, the present invention relates to a USB compatible apparatus for guaranteeing a connection between an optical USB device for inputting/outputting an optical signal and an electrical USB device for inputting/outputting an electrical signal, for example, signal transmission and reception between an electrical USB device (e.g., an electrical USB memory) and an optical USB device (e.g., a computer) having an optical USB port, and a structure of the USB compatible apparatus (a first exemplary embodiment), and to a USB compatible apparatus for guaranteeing signal transmission and reception between an optical USB device (e.g., an optical USB memory) and an electrical USB device (e.g., a portable telephone) having an electrical USB port, and a structure of the USB compatible apparatus (a second exemplary embodiment).
For identification of types of external USB devices in this disclosure, an existing USB device, such as a USB device for inputting/outputting an electrical signal, is defined as an “electrical USB device” and a USB device for inputting/outputting an optical signal is defined as an “optical USB device.”
For example, an optical signal input/output interface scheme is referred to as an “optical serial bus (OSB).” For easy understanding of related techniques, an OSB is referred to as an “optical USB.” Among terms used herein, a male terminal of an interface may be understood as including a plug, and a female terminal may be understood as including a port.
2. Discussion of Related Art
Rapid developments of microprocessor unit (MPU) and memory chip technology have led to a sudden increase of data processing capacity between a computer and a peripheral device. Accordingly, fast signal transmission and highly dense wirings between the computer and the peripheral device are required.
Meanwhile, general-purpose universal serial buses (USBs) are generally used to connect between a computer and a peripheral device.
However, since USBs (with versions 1.0, 1.1, and 2.0) employ an electrical connection scheme (hereinafter, “electrical USB scheme”), there is a limit to which UBSs can keep up with a data processing speed between connected devices. As a result, high-performance MPUs or memory chips do not lead to enhancement of an overall data processing speed.
As an alternative to the electrical USB scheme, an optical USB scheme in which an optical signal is transmitted using optical waveguides has recently been proposed. In the optical USB scheme, for example, optical connections rather than electrical connections are used as buses for connecting between a computer and a peripheral device.
Optical USB schemes for connecting between a computer and a peripheral device include a scheme of using an optical transceiver module and an optical fiber (hereinafter, referred to as “conventional technique 1”) and a scheme of using an optical communication interface (hereinafter, referred to as “conventional technique 2”).
In conventional technique 1, a USB extension device used when a computer having an electrical USB port is far from a printer having an electrical USB plug is embodied by an optical transceiver module and an optical fiber.
However, in conventional technique 1, an interface for the USB extension device must conform to an existing electrical connection scheme in order to connect external devices employing an electrical connection scheme. Conventional technique 1 does not support a data processing speed of a MPU or a memory chip and cannot be directly used for external devices that use optical waveguides to support the data processing speed of the MPU or the memory chip.
Meanwhile, conventional technique 2 provides a module capable of reducing the number of optical fibers using a signal property of the USB. However, conventional technique 2 has a problem connecting external devices employing an electrical connection scheme and does not support connection of external devices using an optical waveguide either.
Thus, since the electrical USB scheme degrades data transmission efficiency due to generation of electromagnetic waves in transmitting high-speed data of 5 Gbps or more, there is a need for USB conversion technology of an optical connection scheme using an optical line for high-speed data transmission.
Meanwhile, since most existing computers, peripheral devices (e.g., printers, mice, and keyboards), portable memories, consumer electronics, portable telephones, content player devices (MP3 players, portable multimedia players (PMPs), and portable game machines), etc. support only an electrical USB interface, there is a need for technology capable of guaranteeing connection compatibility between an electrical USB device and an optical USB device (i.e., a device having an optical USB interface).
For example, there is a need for technology for allowing an optical USB memory to be connected to an existing computer having an electrical USB port for signal transmission and reception or an existing electrical USB memory to be connected to a computer having an optical USB port for signal transmission and reception.
Specifically, there is a need for technology to develop a USB compatible apparatus that is an adaptor capable of connecting external devices with different USB schemes by properly converting a signal input/output to/from an optical USB device according to an existing electrical USB standard and transmitting a resultant signal, or properly converting a signal input/output to/from an existing electrical USB device according to an optical USB standard and transmitting a resultant signal.